BACKGROUND The rate of sICH is rising among young Americans. Trends in acute seizure (AS) incidence in this age group is largely unknown. Further, the association of AS with mortality has not been reported in this age group. We determine trends in AS among young individuals with sICH. METHODS The Merative MarketScan® Commercial Claims and Encounters database, for the years 2005 through 2015, served as the data source. This period was chosen as spontaneous ICH incidence increased among young individuals between 2005 and 2015. Our study population included patients aged 18 to 64 years with ICH identified using the International Classification of Diseases, Ninth and Tenth Revision (ICD-9/10) codes 430, 431, 432.0, 432.1, 432.9, I61, I61.0, I61.1, I61.2, I61.3, I61.4, I61.5, I61.6, I61.8, and I61.9, excluding those with a prior diagnosis of seizures (ICD-9/10 codes 345.x,780.3x, G40, G41, and R56.8). We computed yearly AS incidence, mortality (in patients with and without seizures), and analyzed trends. We applied a logistic regression model to determine the independent association of AS with mortality accounting for demographic and clinical variables. RESULTS AS incidence increased linearly between 2005 (incidence rate: 8.1%) and 2015 (incidence rate: 11.0%), which represents a 26% relative increase (P for trends <0.0001. In-hospital mortality rate was 14.3% among those who developed AS and 11.5% among those who did not. Between 2005 and 2015, overall, in-hospital mortality decreased from 13.0% to 9.7% among patients without AS but remained unchanged among those with AS. Patients who developed AS were 10% more likely to die than those who did not (OR: 1.10, 95% confidence interval: 1.02-1.18). CONCLUSIONS Between 2005 and 2015, AS incidence increased by nearly 26% among young Americans with sICH. In-patient mortality remained unchanged among those who developed seizures but declined among those who did not. The occurrence of AS was independently associated with a 10% higher risk of in-hospital death.

The authors have declared no competing interest.

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This work was supported in part by the comprehensive Health Studies micro-grant program at the Pennsylvania State University.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study protocol was submitted to the Pennsylvania State College of Medicine institutional review board and was not considered to be human subjects research. All records contained within the database are fully de-identified.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

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All data used for this research are publicly available through IBM Watson Health MarketScan® Commercial Claims and Encounters database.